In close medical examinations, in particular in the nature of colposcopy, high magnification at short working distances is required to provide an accurate or useful visual examination, i.e., magnification in the nature of 6.times. to 10.times. or higher. Conventional commercially available colposcopes are large free-standing instruments which are not readily movable due to size. Conventional colposcopes generally cost in the range of from about $4,000-$20,000 and provide magnification in the range of 6.times. to 40.times.. However, the structure of conventional free-standing colposcopes is disadvantageous in that, due to its size, it must be maintained in one location, i.e., one examination room. Further, generally due to cost, a colposcope is shared by multiple doctors. Accordingly, when a colposcopic examination is required, the patient has to be brought to the colposcope. Based on the limited availability of the colposcope, a special appointment time separate from the initial appointment is usually required resulting in additional time and cost to a patient as well as delayed examination. Thus, also, the use of a conventional colposcope as a screening tool is inhibited.
The need, therefore, for a portable magnification apparatus useful as a colposcope is present. A portable colposcopic apparatus would allow for the ready use of the apparatus as a screening tool, thereby increasing the opportunity for diagnosis and treatment. However, known portable magnifying visual apparatus do not allow for adequate magnification which provides an accurate physical examination at close range, such as necessary in the examination of body tissues at a level provided by a colposcope.
For example, U.S. Pat. No. 3,945,712 describes an opthalmoscope and magnifier worn in the manner of eyeglasses. The described opthalmoscope/magnifier utilizes mirrors in order to provide a desired field of vision through the instrument. Depending on the field of vision sought, magnification can be provided or not. Satisfactory magnification for a working distance of 12 inches is described as being from 2.times. to 4.times..
Additionally, U.S. Pat. No. 4,195,918 describes spectacles which can have neutral or prescription lenses in combination with a light means and a magnifying zoom lens. The combined device is described as allowing for the exploration of a field of operation. Working distances of 250-350 mm are described as being provided by the spectacles. The magnification capability of the zoom lens is not set forth, but in view of the structure disclosed, low magnification only would be provided. High magnifications would result in distortions.
Additionally, U.S. Pat. No. 4,834,525 describes spectacles with lenses, which can be prescription lenses, including mounting means for receiving telescopic devices. The telescopic devices can have a binocular focus at a magnification suited to pre-determined working distances. The '525 patent recognizes that working distances will vary depending on the specific use of the spectacles. Beyond this generalization, no specific teaching is set forth regarding the magnification capabilities and working distances. The spectacles described are in the manner of loupes known in the art but having quick release mounts to allow for interchanging different telescopic devices.
Further, magnifying eyeglasses are commercially available for individuals with impaired vision, such as sold under the name "Beecher Mirage" by Beecher Research Company, Schaumberg, Ill. The glasses are monocular or binocular and have a support means positionable on a user's ears so that the glasses can be worn in the manner of conventional eyeglasses. The binocular or monocular lenses allow for improved vision close up or at a distance. The glasses use an internal mirror system and are available in strengths of 4.times.20, 7.times.30 and 10.times.35. In use at high magnifications at close ranges, however, these glasses have a distorted short focal length. Patents disclosing various aspects of the Beecher binocular structure including the mirror or focusing system, mounting means and the like, include U.S. Pat. Nos. 3,918,792; 3,981,021; 3,985,421; 4,140,567; 4,140,568; 4,272,153; 4,488,790; 4,568,154; 4,758,077; 4,779,965; 4,877,318 and U.S. Pat. No. Des. 249,350.
Accordingly, a portable apparatus, in particular worn in the manner of eyeglasses which allow for close-up visual medical examinations would be advantageous in view of the improved opportunity to readily provide examination as needed without relocation of the patient or providing a separate appointment time. Such apparatus would be readily useable and economical, thereby making diagnosis and treatment more readily available and cost efficient.